The overall goal of this project is to develop a computerized self- monitoring system (CSMS) for use in clinical and research settings. The product will be a toolkit that will allow behavioral Scientists with no programming experience to develop and implement a broad range of customized self-monitoring protocols. This product could have broad applicability in a wide range of settings where the collection of data via self-monitoring is emphasized. The toolkit will consist of a hand-held computer (HHC), a front-end software program (FESP) and hardware for exchanging information between the hand-held computer and any other PC. The FESP will be used to develop the assessment protocols. which will then be downloaded to and implemented via the HHC. The HHC will be carried by research subjects or therapy patients and used as an interactive self-monitoring tool. During Phase I, the feasibility of the concept was demonstrated through an evaluation of an early FESP prototype by professional behavioral scientists and a mood assessment study with community volunteers using the HHCs. During Phase II a second generation CSMS will be developed and evaluated in a series of three studies: l) a usability evaluation with professional behavioral scientists: 2) a comparison with paper and pencil monitoring in a chronic pain clinic: and 3) an experience sampling study investigating the relationship between cognitions and symptoms of depression. Following completion of these studies, the CSMS will be modified in preparation for release of a commercial product. PROPOSED COMMERCIAL APPLICATION: This product should have broad commercial appeal among professional behavioral scientists working in either clinical or research settings where the use of self-monitoring is emphasized.